/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.math.collision;

import java.io.Serializable;

import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.math.Vector3;
import com.badlogic.gdx.utils.NumberUtils;

/** Encapsulates a 3D sphere with a center and a radius
 *
 * @author badlogicgames@gmail.com */
public class Sphere implements Serializable {
    private static final long serialVersionUID = -6487336868908521596L;
    /** the radius of the sphere **/
    public float radius;
    /** the center of the sphere **/
    public final Vector3 center;

    private static final float PI_4_3 = MathUtils.PI * 4f / 3f;

    /** Constructs a sphere with the given center and radius
     * @param center The center
     * @param radius The radius */
    public Sphere (Vector3 center, float radius) {
        this.center = new Vector3(center);
        this.radius = radius;
    }

    /** @param sphere the other sphere
     * @return whether this and the other sphere overlap */
    public boolean overlaps (Sphere sphere) {
        return center.dst2(sphere.center) < (radius + sphere.radius) * (radius + sphere.radius);
    }

    @Override
    public int hashCode () {
        final int prime = 71;
        int result = 1;
        result = prime * result + this.center.hashCode();
        result = prime * result + NumberUtils.floatToRawIntBits(this.radius);
        return result;
    }

    @Override
    public boolean equals (Object o) {
        if (this == o) return true;
        if (o == null || o.getClass() != this.getClass()) return false;
        Sphere s = (Sphere)o;
        return this.radius == s.radius && this.center.equals(s.center);
    }

    public float volume () {
        return PI_4_3 * this.radius * this.radius * this.radius;
    }

    public float surfaceArea () {
        return 4 * MathUtils.PI * this.radius * this.radius;
    }
}